I. Technical Field
The present invention relates to the transmission of data over a radio link. More specifically, the present invention relates to a novel data link having multiple parallel data paths which gives it many desirable features that are not present in data links of a conventional design.
II. Background of the Art
Data links encounter many difficulties when operating in hostile conditions such as those in a combat environment. A military data link that will be used in combat needs to be difficult to jam, reliable and have a reasonable price.
A common combat scenario in which data links are employed is one in which data is transmitted between an airborne terminal and a ground terminal in both directions. The airborne terminal has a number of sensors on board, for example, radar, infrared scanners radio receivers and TV, and the data from the sensors is transmitted to ground stations for use by the ground troops. The data link needs to operate in an environment that has jamming and multipath propagation. The data link also needs to be "fail soft" which means it has very few parts that if they failed they would cause the total disruption of the flow of data.
The conventional data links transmit all data on one carrier wave which makes them susceptible to jamming, fading due to multipath and total failures because most of the parts that make up the data link are single point failure parts.
Therefore, it is the object of the present invention to provide a modular data link that has many parallel paths for the data and a corresponding number of carriers so that the link is difficult to jam because if a jammer only jams a few of the carriers the data link can continue to operate. The parallel data paths also makes the link immune to multipath fading because not all carriers will fade simultaneously so that the data link can continue to operate. The parallel data paths also makes the link "fail soft" because a failure in one of the paths will not cause a total failure of the link.